You just need to make sure the bluetooth headset you buy is A2DP capable, and your Android device must also be A2DP capable (if it's a newer Android phone, it more than likely is capable for A2DP bluetooth connectivity).
If the bluetooth is paired and connected to the device, but NOT connected via A2DP, you will only be able to use it for phone calls.
In other words, A2DP bluetooth just means you can listen to Android music apps, voice assistant apps, game apps, and of course navigation through the bluetooth headset.
EDIT... I listen to turn by turn instructions from my Google Navigation GPS app through my bluetooth headset using:
- Motorola Droid Bionic smartphone
- Jawbone Icon A2DP bluetooth headset